1. Field of the Invention
The present invention relates generally to a stump cutting apparatus and, more specifically to a cutting tool for use with a stump cutting apparatus.
2. Description of Related Art
Various types of stump cutting devices are known. A typical stump cutting apparatus includes a rotatable cutting wheel or drum having a plurality of cutting tools fastened circumferentially about the wheel or drum. Some stump cutting devices use a pair of pockets or mounting blocks attached across from each other on opposite sides of the cutting wheel. One of the pockets having at least one, and preferably a pair of, counterbored apertures, extending axially through the pocket. The other pocket having at least one, and preferably a pair of, threaded apertures extending axially through the pocket.
A fastener, such as a bolt or screw, extends through the counterbored aperture in the pocket, an aperture in the cutting wheel, and threadably engages the threaded aperture on the opposite pocket. Accordingly, when the fastener is tightened, it draws the pockets or tool holders together such that they sandwich the cutting wheel between them.
Typically, the pockets or mounting blocks both support and secure a cutting tooth to the cutting wheel. Depending upon the particular cutting tooth design or style a carbide cutting bit is attached to the cutting tooth. In many instances only a portion of the carbide cutting bit actually performs the cutting operation thus wasting the remaining portion or cutting edge of the carbide cutting bit.
Since stump cutting teeth typically operate in a harsh environment, replacement of the cutting teeth is or can be an almost continuous job. For example, contact with the ground surface rapidly dulls the cutting edge of each cutting tooth. In addition, when a cutting tooth strikes something hard such as a stone or rock the cutting bit or an edge thereof may break or chip requiring replacement of the cutting tooth. Finally, continuous loading of the cutting tooth can cause cutting tooth failure including twisting or bending of the shank portion. In some instances, the tooth itself may break thus necessitating replacement. Cutting tooth replacement is costly both in material replacement costs and associated man-hours necessary to remove and install each individual new cutting tooth. Further, depending upon the load applied to the cutting tool during the stump cutting operation, the fastener securing the mounting block or tool holder to the cutting wheel may break or shear.
One type of cutting tooth and tool holder/pocket assembly is disclosed in the U.S. Pat. No. 5,743,314 the disclosure of which is hereby incorporated by reference. As set forth therein, the '314 patent discloses a stump cutting tool assembly including a cutting tooth having an insert made of a solid material such as tungsten carbide and a generally cylindrical shank that extends through an aperture in a mounting block or pocket. As illustrated therein, a pair of fasteners, for example bolts, are used to secure the tool holder/pocket assembly and correspondingly the cutting tooth to a cutting wheel.